In the December issue Callum published an exciting article about video capture using Liberty Basic (check it out here: [http://babek.info/libertybasicfiles/lbnews/nl127/vidcap.htm])

Callum offers the following correction to that article:

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I recently ordered the Microsoft Platform SDK CD in order to get more up to date API documentation. After reading the documentation regarding the frame rate for preview mode I realised that the article I wrote in the newsletter was misleading on frame rate. It turns out the value referred to as frame rate in that article is actually the interval in milliseconds between frames. In other words, the computer waits the specified number of milliseconds before capturing each frame. By using the term 'frame rate' I feel my article implied that this value was the number of frames per second, which it is not.

In theory if the interval is too low you can waste a lot of system resources, but I think this applies more to computers from the Win 3.1 days when Video for Windows was introduced. If you set the interval lower than your device can go, the device simply defaults to its lowest supported interval. The example in the SDK documentation suggested an interval of 60 milliseconds as opposed to the 5 I used in the article.

I would like to apologise if my article mislead or confused anyone on this issue. Hopefully I will be able to avoid any similar errors in the future now that I have complete and up to date documentation.

Callum

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